MPIGate: Passerelle multiprotocolaire pour le maintien à domicile

National audienceMPIGate: Passerelle multi protocolaire pour le maintien à domicil

SCSP : an Energy Efficient Network-MAC Cross-layer design for wireless Sensor Networks

held in conjunction with The 34th IEEE Conference on Local Computer Networks - LCN'09International audienceThis article presents SCSP (for ``Sleep Collect and Send Protocol'') for wireless sensor networks, a network-MAC cross layer design that resolves the inherent conflict between energy efficiency and throughput. The protocol uses in its MAC layer a new paradigm that we call ``sleep, collect and send''. The idea of SCSP is that a router sleeps for a given amount of time, wakes up and collects data from its children and other routers and then send them into a burst during a period of time that we call transmission period. In its network layer, the protocol uses a hierarchical tree structure as network architecture and a tree routing protocol. SCSP does not require synchronization between routers and dynamically calculates the sleep and collect periods according to the amount of incoming traffic. The protocol is implemented and simulated in OPNET simulator

MPIGate : Multi Protocol Interface and Gateway

International audienceAbstract: We present MPIGate, a multiprotocol gateway and interface for assisted living applications. This project aims to facilitate the development of applications thanks to the abstraction of sensing data and the facility of access to read and write functions over the devices plugged to the network. The contribution includes modularity and a middleware layer offering modularity and quality of service. The proposed unified syntax of messages facilitates interconnection with other systems, networks and devices

Planar p-n Junction Based on a TMDs/Boron Nitride Heterostructure

Transition metal dichalcogenides (TMDs) are attracting growing interest for their prospective application in electronic and optical devices. As a leading material in researches of two-dimensional (2D) electronics, although band structure is layer-dependent, the TMDs show ambipolar properties. While optically excited light emission has been widely investigated, study on electrically generated emission is still limited. Taking the advantage of its ambipolarity and presence of direct band-gap in monolayer, we developed an electrically driven light emitting device based on stacked 2D flakes to obtain sharp planar p-n junction in monolayer. Specifically, we have fabricated atomic-layer TMDs/boron nitride (BN) artificial heterostructures using stacked h-BN thin flake as a mask to partially cover the TMDs transistor channel allowing high-density hole accumulation (p-region) via localized exposure to gate-controlled accumulation of anions. Transport through the junction shows typical diode-like rectification current with accompanying strong and sharp light emission from the crystal edge of BN mask for the monolayer case.</p

MPIGate: A Solution to use Heterogeneous Networks for Assisted Living Applications

International audienceExisting sensors and actuators, that can be used in an AAL (ambient assisting living) environment, work on het- erogeneous network protocols, e.g., WiFi, Bluetooth, EIB/KNX and Zigbee. For a given sensor/actuator, the choice of its underlying communication protocol is optimized according to its bandwidth and/or energy needs. However, integrating sensors/actuators of heterogeneous network protocols into an AAL system arises interoperability problems. In this paper, we present MPIGate, a multi-protocol gateway and interface for assisted living applications. Besides its multiple communication drivers for supporting the different protocols, MPIGate also proposes a database for storing the last updated sensor data as well as an user interface for both transparent data access and easy application development. MPIGate has been deployed in a smart home technical test bed at our LORIA labs. We presents some first results and discuss the lessons learnt

Operator Calculus Approach to Minimal Paths: Precomputed routing in a Store and Forward Satellite Constellation

To appearInternational audienceAn innovative minimal paths algorithm based on operator calculus in graded semigroup algebras is described. Classical approaches to routing problems invariably require construction of trees and the use of heuristics to prevent com- binatorial explosion. The operator calculus approach presented herein, however, allows such explicit tree constructions to be avoided. Moreover, the implicit tree structures underlying the problem are pruned automatically by the inherent properties of the semigroup algebras used in this approach. The operator calculus algorithm proposed here is applied to the problem of precomputed routing in a store-and-forward (S&F) satellite constellation, which provides message communication services by relaying messages between satellites through gateways on the ground. The minimum end-to-end delay paths obtained are compared with the best existing heuristics-based results. The best existing results were obtained from a greedy algorithm designed to explore only a portion of the solution space in order to avoid combinatorial explosion and memory overload. In all test cases, the operator calculus is shown to return paths whose minimum end-to-end delay is either equal to or less than that of the best existing result. In some cases, in which the tree pruning algorithm did not find a solution, the operator calculus does. These results correspond to a one-single constraint case considering the end-to- end delay as the cost of the links, if the case of multi constraints is considered (e.g. bandwidth, rapidity,. . . ) the operator calculus approach can be similarly used

Charge photogeneration in few-layer MoS2

The two-dimensional semiconductor MoS2 in its mono- and few-layer form is expected to have a significant exciton binding energy of several 100 meV, leading to the consensus that excitons are the primary photoexcited species. Nevertheless, even single layers show a strong photovoltaic effect and work as the active material in high sensitivity photodetectors, thus indicating efficient charge carrier photogeneration (CPG). Here we use continuous wave photomodulation spectroscopy to identify the optical signature of long-lived charge carriers and femtosecond pump-probe spectroscopy to follow the CPG dynamics. We find that intitial photoexcitation yields a branching between excitons and charge carriers, followed by excitation energy dependent hot exciton dissociation as an additional CPG mechanism. Based on these findings, we make simple suggestions for the design of more efficient MoS2 photovoltaic and photodetector devices

Pmcmtp's Implementation (in nesC/TinyOS2.x) and Testbed for Its Operation Validation

International audiencePMCMTP is a Prioritized Multi-Channel Multi- Time slot MAC protocol that the authors have proposed for allowing to simultaneous use of several frequency channels. This protocol is designed for UWB of IEEE802.15.4a but it can also be used over IEEE802.15.4. In this paper, we design and implement a testbed of this protocol to demonstrate its practical implementability. Due to the unavailability of UWB transceiver, the testbed has been performed using classic 2.4GHz WSN transceivers. To reduce the complexity of resource sharing, the global network is composed of a set of Personal Area Networks (PANs) or cells. So, the PMCMTPs experiments are performed for a single PAN and two PANs

The effects of whole‐body vibration amplitude on glucose metabolism, inflammation, and skeletal muscle oxygenation

Whole‐body vibration (WBV) is an exercise mimetic that elicits beneficial metabolic effects. This study aims to investigate the effects of WBV amplitude on metabolic, inflammatory, and muscle oxygenation responses. Forty women and men were assigned to a high (HI; n = 20, Age: 31 ± 6 y) or a low‐amplitude group (LO; n = 20, Age: 33 ± 6 y). Participants engaged in 10 cycles of WBV [1 cycle =1 min of vibration followed by 30 s of rest], while gastrocnemius muscle oxygen consumption (mVO(2)) was assessed using near‐infrared spectroscopy (NIRS). Blood samples were collected PRE, POST, 1H, 3Hs, and 24H post‐WBV and analyzed for insulin, glucose, and IL‐6. In the LO group, Homeostatic Model Assessment for Insulin Resistant (HOMA‐IR) at 3 h (0.7 ± 0.2) was significantly lower compared to PRE (1.1 ± 0.2; p = 0.018), POST (1.3 ± 0.3; p = 0.045), 1H (1.3 ± 0.3; p = 0.010), and 24H (1.4 ± 0.2; p < 0.001). In addition, at 24H, HOMA‐IR was significantly lower in the LO when compared to the HI group (LO: 1.4 ± 0.2 vs. HI: 2.2 ± 0.4; p = 0.030). mVO(2) was higher (p = 0.003) in the LO (0.93 ± 0.29 ml/min/100 ml) when compared to the HI group (0.63 ± 0.28 ml/min/100 ml). IL‐6 at 3H (LO: 13.2 ± 2.7 vs. HI: 19.6 ± 4.0 pg·ml(−1); p = 0.045) and 24H (LO: 4.2 ± 1.1 vs. HI: 12.5 ± 3.1 pg·ml(−1); p = 0.016) was greater in the HI compared to the LO group. These findings indicate that low‐amplitude WBV provides greater metabolic benefits compared to high‐amplitude WBV